#65 Eggplant – It turns out (I googled “iron containing enzymes”) that iron is needed as a coenzyme in dozens of metabolic enzymes, including several of the ones needed for the synthesis of RNA and DNA and several more involved in the control of reactive oxygen species. Iron really is a growth limiter in a lot of places in the ocean.

Regarding your #61, it is quite possible that the issue of phytoplankton and global warming is one of those nasty little feedback loops, specifically with respect to CO2 levels. Less plankton means more CO2, obviously. But more dissolved CO2 also means less plankton, by another route. Many plankton species use some variety of calcium carbonate as part of their structure, and more acid water caused by increased dissolved CO2 makes it more difficult for the plankton to deposit CaCO3 into those structures.